While photographing Baya Weavers Ploceus philippinus at a site near Lim Chu Kang in western Singapore during May 2008 certain unexpected observations were made regarding adult male behaviour at the nest.
Baya Weavers have a wide geographical range, from Pakistan through S and SE Asia to Sumatra, Java and Bali (but not including the Philippines as their Latin name would seem to suggest), and their biology is generally fairly well understood. In Singapore, they occur wherever suitable grassland habitat occurs as they need the tall lalang grass to build their nests. Unfortunately, the area of suitable habitat in the Republic is shrinking as more land is developed, but still there appears to be a stable population.
My original interest was to photograph the female Baya Weaver flying into the nest to deliver food, and to capture images of the beauty and grace of the bird in this behaviour. Armed with a suitable telephoto lens I selected a small nesting colony of Baya Weavers on an African Tulip Tree Spathodea campanulata in Western Singapore in early May 2008.
My first observation was that getting close enough to obtain reasonably sized photos caused the Baya Weaver colony to became excited or alarmed, but that they calmed down and stopped chirping when I moved away a short distance. So I made a 20 m. length of wired cable release that allowed the camera to be positioned next to the nest, but with the photographer far enough back for the birds’ comfort. They were completely oblivious to the camera and behaved normally at the distance I remained from the colony. No flash was used; all images were taken with natural light.
The colony consisted of 8 active nests and 5 incomplete, ‘helmet-stage’ nests. For photographic purposes, I paid most attention to two active nests with good backgrounds, one of which had an open background (“blue sky”), the other a leafy background (“green”). Ten trips were made to the colony, from 9 May to 2 June. Initially, the observations were as expected; the two females delivered food to their nestlings at regular intervals, and the nestlings seemed rather advanced as they were heard calling when the female entered the nest. Initially, all photography was concentrated on the “green” nest. Then on 12 May the author noticed a male enter the “blue sky” nest, without food, and to quickly leave again. The following day, the presumed same male entered the same nest a couple of times, again without food.
Consequently I switched my attention from the female, to photographing the male with his bright yellow cap. On 15 May the male was seen entering the “blue sky” nest with food, and this nest was then photographed exclusively through to 21 May. During this period he continued to take turns with the female delivering food to the nest. The feeding interval varied but increased to about six times per hour towards the later days, with the male actually a bit more active, delivering about 4 times out of the 6 per hour. When I returned on May 22, this nest had already fledged.
From 22 May onwards I photographed a male entering the “green” nest, and similar observations, but without photographs, were made of the other active nests in the colony, with males bringing in food.
Another observation of interest was the difference between how the male and female exited the nest. The female literally just shot out of the nest at an unpredictable time, making photography difficult. The male, however, clung onto the nest entrance upside down and looked around for a few seconds before letting go and flying off. The behavioural difference between male and female was consistently repeated.
After 23 May a period of dark, rainy weather occurred, and on the next visit on June 2, all the remaining active nests had fledged. All the fledged nests were lying under the tree, and breeding males had started construction of several fresh helmets.
I then enthusiastically read all the available information on the Baya Weaver on the Internet and in the reference books available. All popular Internet sites found, including Wikipedia and several based in Singapore, state that as the male is polygynous and that after he mates with the first female, he will try to mate with one or two more. Subsequently, only the female attends to incubation and to the nestlings. In ‘The Birds of the Thai-Malay Peninsula’, David Wells says the same. However, I was able to find references by Suhel Quader that, in S Asia, male Baya Weavers occasionally do bring food to the nest.
In my opinion, the male behaviour of hanging onto the nest upside down before flying away after delivering food seemed to be an extension of the male advertising behaviour, where he hangs onto the helmet and advertises for a mate. Because the male appeared to make inspection tours of the nests to gauge development before joining the feeding activity, I also suspect that males bring food to the nest only in the last few days prior to fledging, when the nestling’s demands would be at a maximum and perhaps more than the female could undertake alone. Of course, this theory would have to be tested at more colonies in other locations, and a closer check would need to be made of whether the males that exhibit this behaviour are monogamous or polygamous. Or perhaps it is just Singapore birds that have been so democratic as to share the duties between the male and female!
It is hoped that others will follow up and advance these observations, and if you are going to take pictures please keep a safe distance.
Wells, D. R. 2007. The Birds of the Thai-Malay Peninsula. Vol. 2, Passerines. Christopher Helm, London.
Lim Kim Seng: The Avifauna of Singapore
Lim KC & KS: State of Singapore’s Wild Birds and Bird Habitats
Quader, Suhel: http://www.ncbs.res.in/suhel/index.html [30 Aug 2009]
I have learned that male feeding behavior has been seen before, but perhaps these are among the first photos.
A version of this article appeared in Nature Watch (a publication of Nature Society Singapore) in Vol 17 No 3 Jul-Sep 2009